Enhancing energy harvest in a constructal solar collector by using alumina-water as nanofluid. (1st May 2017)

• Record Type: Journal Article
• Authors: Ojeda, J.A.; Messina, S.
• Is Part Of: Solar energy. Volume 147(2017)
• Page Start: 381
• Page End: 389
• Publication Date: 2017-05-01
• Subjects: Nanofluid -- Constructal design -- Solar energy -- Solar collector; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2017.03.054
• Languages: English
• ISSNs: 0038-092X

Abstract

Highlights: A branched pipe network in a solar collector with a disc-shaped body for a nanofluid flow is developed. The size of the pipe network for a nanofluid flow are smaller than a base fluid flow. Optimal size of ramifications and thermal resistance of every level of construction are obtained for a nanofluid flow. Abstract: We have developed a network of pipes of dendritic geometry in a solar collector with a disc-shaped body. The fluid in the network pipes is a nanofluid composed of a mixture of nanoparticles of alumina (Al2 O3 ) and water as a base fluid in order to harvest a greater amount of thermal energy from incoming solar radiation. The sizes of the network pipes are obtained by using constructal theory methods. Thermal conductivity was obtained by the Hamilton-Crosser model; physical properties such as density and specific heat capacity were described as a function of the volumetric fraction of nanoparticles in the fluid. Optimal size of the network presented for every level of construction was established by the condition of minimal thermal resistance. Temperature profiles and the aspect ratio of the construction elements were defined as a function of the volumetric fraction of nanoparticles. Results show that by increasing the volume fraction of nanoparticles, thermal energy gain also increases, reaching a higher outlet temperature of the fluid when alumina nanoparticles are used.